Texas Instruments TI 99/4a Books
The Texas Instruments TI-99/4A was an early home computer, released in June 1981, originally at a price of US$525. It was an enhanced version of the less successful TI-99/4 model, which was released in late 1979 at a price of $1,150. The TI-99/4A added an additional graphics mode, "lowercase" characters consisting of small capitals, and a full travel keyboard. Its predecessor, the TI-99/4, featured a calculator-style chiclet keyboard and a character set that lacked lowercase text.